EZP-22318: Added tests
EZP-22318: Force legacy kernel to use Symfony session cookie settings

Depends on https://github.com/ezsystems/ezpublish-legacy/pull/881
Changed dependency on Symfony to 2.3.*

Problem is there is a BC break in Symfony 2.4 in fragment renderers.
A 4th argument "strict" was added in generateFragmentUri() method.